Computer Help Needed...

I have an older sony Vaio PC. Probably about 10 years old. It has windows XP. I just now got it up and running after probably about 5 years of dormance. All has been working fine.

Today, I turned it on and when the sign in screen comes up to enter my password, everything looks like double or even triple vision. When I try to sign in my password, the screen goes black and then comes back up in a few minutes. Same thing when I try to sign in again. It was online a while back but now I could not get it to connect. I hopw it is something simple as this has my desktop dyno program in it and a lot of saved info in that program. When I first turn it on, all of the writing on the boot up screen looks fine and also the big windows logo screen looks good. It's just the password sign in screen that's boogered up and I cannot get past it. I've restarted several times to no avail. Any ideas? Thanks.